going to get cancer. they found that 1,290 men who were taking vitamins developed cancer over that 11-year period and 1,379 who were taking placebos developed cancer. as you can see, there is a difference. in fact, it's a statistically significant difference. it's not gigantic. again, it's not gigantic, but there is a difference there. >> it's a multi-vitamin, it makes you wonder which vitamin works to prevent cancer. >> right. i think they really don't know. it's interesting, because they found it worked better for some cancers than others. for example, for prostate cancer, that didn't seem to be significant. but, yeah, it could be one of a whole bunch of things. antioxidants. it's not entirely clear. >> wow! i guess you should go ahead if you're a middle-aged guy and take a multivitamin? >> that's, of course, what you might think from this. i want to sort of put this in context. there have been some studies that show that there might possibly be some problems with taking a multivitamin. so, this is a decision that you have to make. the american cancer society, their bottom line is, we want to see more studies.